Radio-Anatomical Evaluation of Cephalic Index amongst Nigerians Using Computed Tomography (CT)

Background: Cephalic Index (CI), also known as cranial index is the ratio of maximum breadth to length of the head multiplied by 100. It is a commonly used anthropometric parameter in determining the racial variation and sex differences. The aim of this study was to determine the cephalic index amongst Nigerians, using computed tomography (CT). Objectives: To measure the length and breadth of the skull, to determine the cephalic index of the skull, and to check for sexual dimorphism. Methods: This retrospective study was carried out in the Radiology department of the Rivers State University Teaching Hospital Port Harcourt with ethical approval. One hundred and fifty CT images (2021-2022) of 150 patients (75 males and 75 females), 18 years and above were used in this study. The maximum length of the skull was measured as the distance between the glabella and the most projecting point at the back of the head (inion), and the maximum breadth of the skull was also measured as the distance between the most projecting points at the sides of the head (parietal tuber), both length and breadth were measured at the level of the lateral ventricle of the brain. Results: Data was analyzed using the Statistical Package for the Social Sciences (SPSS IBM version 23.0) and Microsoft excel 2019 edition. The mean values for the measured parameters include length [male (185.64±6.40); female (179.60±6.54)], breadth [male (138.56±5.10); female (135.66±5.81)] and cephalic index [male (74.70±3.30); female (75.60±3.68)]. Cephalic index was not statistically significant (t-value = -1.57; P = 0.12). Conclusion: Three major head types were found in this study; doliocephalic (52.6%), mesocephalic (37.3%), and brachycephalic (10%), therefore doliocephalic head type (long head) is the most dominant in the sampled population. There was no sexual dimorphism in cephalic index.